Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> --- include/linux/cpuhotplug.h | 1 + lib/percpu_counter.c | 25 ++++++++++++++----------- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index c622ab349af3..04e5f99ffc70 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -33,6 +33,7 @@ enum cpuhp_state { CPUHP_FS_BUFF_DEAD, CPUHP_PRINTK_DEAD, CPUHP_MM_MEMCQ_DEAD, + CPUHP_PERCPU_CNT_DEAD, CPUHP_WORKQUEUE_PREP, CPUHP_POWER_NUMA_PREPARE, CPUHP_HRTIMERS_PREPARE, diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 72d36113ccaa..c8cebb137076 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -158,25 +158,21 @@ EXPORT_SYMBOL(percpu_counter_destroy); int percpu_counter_batch __read_mostly = 32; EXPORT_SYMBOL(percpu_counter_batch); -static void compute_batch_value(void) +static int compute_batch_value(unsigned int cpu) { int nr = num_online_cpus(); percpu_counter_batch = max(32, nr*2); + return 0; } -static int percpu_counter_hotcpu_callback(struct notifier_block *nb, - unsigned long action, void *hcpu) +static int percpu_counter_cpu_dead(unsigned int cpu) { #ifdef CONFIG_HOTPLUG_CPU - unsigned int cpu; struct percpu_counter *fbc; - compute_batch_value(); - if (action != CPU_DEAD && action != CPU_DEAD_FROZEN) - return NOTIFY_OK; + compute_batch_value(cpu); - cpu = (unsigned long)hcpu; spin_lock_irq(&percpu_counters_lock); list_for_each_entry(fbc, &percpu_counters, list) { s32 *pcount; @@ -190,7 +186,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb, } spin_unlock_irq(&percpu_counters_lock); #endif - return NOTIFY_OK; + return 0; } /* @@ -222,8 +218,15 @@ EXPORT_SYMBOL(__percpu_counter_compare); static int __init percpu_counter_startup(void) { - compute_batch_value(); - hotcpu_notifier(percpu_counter_hotcpu_callback, 0); + int ret; + + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "lib/percpu_cnt:online", + compute_batch_value, NULL); + WARN_ON(ret < 0); + ret = cpuhp_setup_state_nocalls(CPUHP_PERCPU_CNT_DEAD, + "lib/percpu_cnt:dead", NULL, + percpu_counter_cpu_dead); + WARN_ON(ret < 0); return 0; } module_init(percpu_counter_startup); -- 2.10.2
